The invention relates to a connecting cable comprising a cable with a large number of conductors, which are routed in pairs in a defined manner in the cable, with an identical electrical plug connection being arranged at both ends of the cable, with a cable manager being arranged at each of the two cable ends for fixing and defined guidance, in which cable managers the conductors of the cable are routed to the electrical contacts.
The most widely used electrical plug connection for symmetrical data cables is the RJ-45 plug connection (Regular Jack 45), various versions of which are known depending on the technical requirement. For extremely high data transmission rates, compensation measures are required in the socket to reduce the overall crosstalk to the necessary extent. However, this requires tight tolerances for the crosstalk in the connector. In order to provide compatibility with components from other manufacturers, the crosstalk in the connector must be defined within a narrow tolerance band for each combination of pairs.
The crosstalk in RJ-45 connectors can be defined by the physical configuration of the parallel-arranged contacts and of the parallel routing of the conductors. At the junction to a cable, the crosstalk between the conductor pairs is subject to very wide tolerances in this area, depending on where the twisting of the conductor pairs starts and the extent to which conductors in adjacent pairs touch. The required crosstalk levels cannot be guaranteed in this simple way.
Compliance with the required crosstalk levels in a connector requires that the conductors be fixed in a defined manner in the area where the conductor pairs are routed without being twisted and changes in the position invariably result in changes in the crosstalk between the conductor pairs. This fixing of the conductors is carried out by means of a cable manager.
Such a cable manager is disclosed, for example, in EP 0 789 939 B1. This has guides on the bottom face and on top face, in which the conductor pairs are routed in a defined manner. The conductors are in this case routed within the cable manager essentially at right angles to the end surface of said cable manager, with the conductors being routed behind the cable manager into a common connecting plane, where they are then connected to the contacts. In this case, the two outer conductor pairs are routed at the sides on the bottom face and top face of the opposite ends while, in contrast, the two inner conductor pairs for the interleaved contacts are routed virtually one above the other on the top face and bottom face. However, if two identical electrical plug connections, for example for a patch cable or connector cable, are now intended to be connected to the two cable ends, then this leads to two conductor pairs having to be crossed over at one end of the cable, which leads to undesirable crosstalk, so that the predetermined narrow tolerance bands can no longer be complied with.
Such a patch cable or connector cable is known from the 1998 Telecommunications and Data Components of the Product Catalogue from CobiNet GmbH, April 1998, page 2.3. The prospectus does not indicate the internal design or whether a cable manager is used, and how this is constructed.
The invention is thus based on the technical problem of providing a connecting cable of this generic type, in which the tolerances in the crosstalk levels at both ends of the cable are minimized. A further technical problem is to provide a cable manager for this purpose.
The technical problem is solved by the subject matters of the features of patent claims 1, and 9. Further advantageous refinements of the invention result from the dependent claims.
To this end, from the rear face to the end surface in the first cable manager, a first inner conductor pair is routed from the top face, and a second inner conductor is routed from the bottom face of the cable manager into a connecting plane, without crossing and, from the rear face to the end surface in the second cable manager, the first inner conductor pair is routed from the bottom face, and the second inner conductor pair is routed from the top face, into a connecting plane without crossing. Use is in this case made of the fact that, by virtue of the twisting, two conductor pairs can in each case be routed on the same side on both sides of the cable, while the two other conductor pairs interchange their sides. Either the two outer pairs or the two inner pairs can thus be routed in the same way at the two electrical plug connections. Since the two outer conductor pairs would have to be interchanged over the full width of the cable manager, the two inner conductors pairs are in each case routed such that they are interchanged at the two cable managers. In consequence, the two inner conductor pairs can be routed into their connecting plane at both ends in a well-defined manner, without crossing over.
In one preferred embodiment, the two inner conductor pairs lie in the same connecting plane E1. In consequence, the two inner conductor pairs lie close to one another and produce crosstalk which is required for compatibility purposes. Since the crosstalk is produced in the connecting plane, it does not need to be produced by the conductor pairs having a specific course with respect to one another in the cable manager, so that the longitudinal dimensions of the cable manager can be kept very small and compact.
In a further preferred embodiment, the connecting plane of the inner conductor pairs lies on the top face of the cable manager, so that one conductor pair is in each case looped virtually straight through the cable manager at each end. This reduces the mechanical requirements for the cable managers since only one pair of conductors need change plane in each case.
The routing of the inner conductor pairs, or the one inner conductor pair, in the cable manager, is designed to be diagonal or vertically angled, in order to change the connecting plane. The advantage of diagonal routing is its simple implementation, since only continuous routing is required while, in contrast, the advantage of vertical angling is that the two inner conductor pairs can be routed at a greater distance from one another in the cable manager, so that the crosstalk is reduced.
In the case of interleaved contact arrangements such as the RJ-45 plug connection, the first inner conductor pair is routed in a V-shape or U-shape with respect to one another in the cable manager.
In a further preferred embodiment, the cable managers are equipped with latching means, so that the cable managers can be latched into the electrical plug connection.
The cable manager according to the invention comprises a non-conducting base body, which is constructed with guides for conductors, in which case the guides for the two outer conductor pairs are constructed essentially at right angles to one end surface at the side in the cable manager, and, from the rear face to the end surface of the cable manager, a first and a second inner pair are in each case routed in pairs from the top face and the bottom face within the cable manager into a common connecting plane E1. in the end surface. The cable manager thus allows the plane of the conductor pairs to be changed from the rear face to the end surface without crossing. Since the changing of the two inner conductor pairs at the two cable ends must actually be reversed, the cable manager must either alternatively allow both guides, or else two cable managers of different design must be used for the two cable ends. In the case of contact arrangements which are not interleaved, the guides may be constructed identically, so that there is no problem in using an identical cable manager for both cable ends. In the case of interleaved contact arrangements, on the other hand, the two guides for the conductors differ. In this case, if the same cable manager is used, the cable manager must in each case provide guides for both the first and second inner conductor pairs on the top face to the end surface and on the bottom face to the end surface. Particularly with continuous guides, this is very complex. It is thus feasible to guide the conductor pairs only in sections within the cable manager, for example on the rear face and on the end surface of the cable manager, with the two inner conductor pairs then being routed differently in between. A disadvantageous feature of the last variant is that the conductors then require a certain amount of play between the two guides on the rear face and on the end surface and thus somewhat increase the tolerances for crosstalk depending on the distance over which the conductors are routed through the two guides.
Two different cable managers are thus used in one preferred embodiment. In the first cable manager, the guide for the first inner conductor pair is routed from the top face into the connecting plane E1 in the end surface, and the guide for the second, inner conductor pair is routed from the bottom face into the common connecting plane E1. The guides in the second cable manager are constructed such that they are interchanged in a corresponding manner.
The connecting plane E1 is preferably arranged under the top face, so that the conductor pair located at the top face on the rear face can in each case be routed virtually straight through the cable manager without changing the plane. A corresponding situation arises if the connecting plane is arranged under the bottom face. The decision as to whether the connecting plane is associated with the top face or bottom face depends on the side from which the contents are intended to make contact with the conductors.
In the case of interleaved contact arrangements, the guide for the first inner conductor pair is constructed at least partially in a U-shape or V-shape.
In a further preferred embodiment, the guides from the rear face to the end surface are in the form of continuous channels, so that the conductors are routed in a defined manner over the entire length of the cable manager.